Envelope construction



May 9, 1961 D. cs. PETERSON ENVELOPE CONSTRUCTION Filed June 23, 58

United States Patent 2,983,485 ENVELOPE CONSTRUCTION I DavidG; Peterson, Wellsvill'e,-N.Y., assignor' to The Air Preheater Corporation, New York, N.'Y., a corporation of New York Filed June ze,,1 9ss,"ser. No. 743,892

The present invention relates to an improved plate type heat exchanger utilizedfor the'transmission of heat between .two confinedfluids, and more-particularlyit relates to an improvedenvelope component that is adapted for assembly .into a plate type heat exchanger.

A'typical' plate type heat exchange apparatus for the transfer-of heat between two confined 'fluids comprises a plurality of spaced metallic plates forming passages through alternate ones of which a relatively hot gas flows in heat exchange relation with air or other fluid to be heated that in turn traverses the intermediate passages. In many such heat exchangers a series of envelopes are provided each comprising a pair of parallel plates with the space therebetween closed along one pair of opposite edges to bound the sides of a passage for one of the fluids. The envelopes are mounted in a spaced parallel relationship to form therebetween a passage for a second fluid, the inter-envelope spaces being closed along one pair of opposite side edges to direct the flow of fluid therethrough. A series of such envelope spaced apart form a heat exchanger core that is then enclosed in a housing having inlet and outlet manifolds leading-to and away from the gas and air passages through the heat exchanger.

The component parts of such heat exchanger apparatus are usually brazed together into an envelope and the envelopes are subsequently assembled and bonded together into an integral body including inlet and outlet manifolds.

Before the advent of the high temperature and high pressure conditions that now prevail in gas turbine practice, a brazed heat exchanger was considered satisfactory in most respects in that the brazed joints thereof would withstand normal conditions of pressure and temperature for long periods of time. Currently however, conditions of temperature and pressure are such that known brazing procedures are generally not adequate, and when subjected to these conditions, most brazed assemblies fail after a relatively short period of service.

For this reason, the principle object of this invention is to provide a basic component for a plate type heat exchanger that is inherently strong.

It is a further object of this invention to provide a heat exchanger component that is readily fabricated by a process of welding and is easily adapted to fabrication by automatic processes.

These and other objects of my invention will become more apparent when considered in view of the accompanying drawings in which:

Figure l is a perspective view of a heat exchange envelope (partly in section) as constructed according to my invention.

Figure 2 is a perspective view of a series of heat exchange envelopes combined to form a multi-fluid heat exchanger.

Figure 3 is a cross section of a single throat member showing the relative proportions of the angular flanges thereof.

r 2,983,485 Patented May 9 1961.

ICC V 2 plate type heat. exchanger comprises a pair of parallel end bars 10 that are spaced apart a. predetermined dis; tance from the ends of a pairof. parallel" closure bai's 1 2 to. provide similar gaps or ports-14 between adjacentends of the spaced bars. A pair of throat members, 16 are bonded tosoppo'si'te sidesof the arem and 12*, joining the spaced ends thereof to form/an integral;

' frame-like member having imperforate ends and ported:

sides. The throat members 16 have an angularcross: section with one flange 18 thereof preferably formed with substantially. greater thickness than flange 20 that'ex tends normal thereto. The flanges 20 are in each in stance connected to endsof adjacent frame members, and in order that the surface 22 of each flange will lie 'in the same plane as the adjacentsurfaces of frame mem-I bers 10 and '12, the endsof each. framev member are; notched as seen at 24 toreceive the narrowflange e20} of each throat member-16. The composite lateral'fls i faces of the frame members are therefore flush. thus; presenting. a pair of opposing plane surfaces to each of which a plane plate 26 isbonded to enclose anjnte gral" envelope having inlet and outlet ports 14' at oppo changer and the'inter-envelope spaces at opposite ends thereof to direct fluids to and from the heat exchanger for flow therethrough in heat exchange relation one with another. I

The sequence of assembling a heat exchanger as herein defined is such that bonding the component elements into an integral frame subsequent to bonding a series of such frames into a heat exchanger of predetermined capacity is noted by the comparative ease with which the elements are joined, inasmuch as each surface so joined is at the time of the bonding operation readily accessible for the utilization of the most desirable manual or automatic welding procedures.

If it is deemed essential to the operation of the heat exchanger disclosed, extended surface means in any of its various forms may be readily applied to one or both sides of sheets 26 prior to their being bonded to opposite sides of the frame-like member comprised of bars 10 and 12, and throat member 16.

Furthermore, it is completely within the scope of this invention to make various other changes such as eliminating the closure bars 12 and extending throat members 16 between end bars 10 to provide a single port on a pair of opposite sides of the envelope for the inlet and outlet ports of a cross flow heat exchanger.

It is evident that different changes may be made without departing from the spirit of the invention and it is therefore intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

In the drawings a basic envelope component for a What I claim is:

1. A plate type heat exchanger having a plurality of envelopes spaced apart to provide inter-envelope passageways for one fluid, while the space through the several envelopes provides other passageways for the flow of a second fluid, said envelopes each including a rectangular frame that comprises a pair of parallel end bars; apair of side closure bars, said closure bars positioned normal to and intermediate the parallel end bars to provide a gap" between their respective ends; throat members bridging the gap between the spaced end bars and closure bars adapted to provide access ports through theframe into each envelope; s'aid throat members comprising a pair of angular bars on laterally opposite sides, of

each gap'having one leg thereof rabbeted to the spaced end and closure bars, while the other leg of each angular bar extends perpendicularlya'way from said frame to provide means spacing an adjacent envelope; a metallic sheet bonded to laterally opposite sides of each frame to define walls separating the passageways through the envelopes'from the inter-envelope passageways; and plate means bonded. to opposite sides of a series of adjacent envelopes bridging the space between closure bars to provide a pair of opposing walls for each inter-envelope passiag'eway. I

2. A plate type'heatexchanger having a plurality of envelopes spaced apart to provide inter-envelope passageways for one fluid, while the space throughthe several envelopes'provides other passageways for the flow 015 a second fluid, said envelopes each including a rectang'ular frame that comprises a pair of parallel end bars; a pair of closure bars, said closure bars positioned normal to and intermediate the parallel end bars with a gap between their respective ends; throat members bridging each gap between the spaced end bars and closure bars to enclose the gap and provide access ports throughthe frame into each envelope, said throat members having an angular cross-section including one leg thereof rabbeted to spaced end and closure bars while the other leg thereof extends normal thereto into contacting engagement with a similar leglextending outward from an adjacent envelope, a metallic sheet bonded to laterally opposite sides of each frame to define walls separating the passageways through the envelopes from the inter-envei-i lope passageways; and plate meansv bonded to opposite sides of a series of adjacent envelopes bridging the space between closure bars to provide a pair of opposing walls for each inter-envelope passageway.

References Cited in the file of this patent UNITED STATES PATENTS 

